How do you do this, i don't understand?

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?

Frank owns a $141,000 home, for which he has a 30-year mortgage in the amount of $700 a month. once he has paid off mortgage, how much will he have paid in investment? a. $111,000 b. $109,000 c. $120,000 d. $141,000

What is the value for this expression? 2e-5